1. Field of the Invention
The present invention generally relates to athletic footwear and, more particularly, is concerned with an athletic footwear sole construction having a combination of structural features enabling enhanced storage, retrieval and guidance of wearer muscle energy in a manner that complements and augments performance of participants in recreational and sports activities.
2. Description of the Prior Art
The increasing popularity of athletic endeavors has been accompanied by an increasing number of shoe designs intended to meet the needs of the participants in the various sports. The proliferation of shoe designs has especially occurred for the participants in athletic endeavors involving walking and running. In typical walking and running gaits, it is well understood that one foot is on the ground in a "stance mode" while the other foot is moving through the air in a "swing mode". Furthermore, in the stance mode, the respective foot "on the ground" travels through three successive basic phases; heel strike, mid stance and toe off.
Current shoe designs fail to adequately address the needs of the participant's foot and ankle system during each of these successive stages. Current shoe designs cause the participant's foot and ankle system to lose a significant proportion, by some estimates at least thirty percent, of its functional abilities including its abilities to absorb shock, load musculature and tendon systems, and to propel the runner's body forward. This is because the soles of current walking and running shoe designs fail to address individually the muscles and tendons of a participant's foot. The failure to individually address these foot components inhibits the flexibility of the foot and ankle system, interferes with the timing necessary to optimally load the foot and ankle system, and interrupts the smooth and continuous transfer of energy from the heel to the toes of the foot during the three successive basic phases of the "on the ground" foot travel.
Historically, manufacturers of modern running shoes added foam to cushion a wearer's foot. Then, gradually manufacturers developed other alternatives to foam-based footwear for the reason that foam becomes permanently compressed with repeated use and thus ceases to perform the cushioning function. The largest running shoe manufacturer, Nike Inc. of Beaverton, Oreg., has utilized bags of compressed gas as the means to cushion the wearer's foot. A German manufacturer, Puma AG, has proposed a foamless shoe in which polyurethane elastomer is the cushioning material. Another running shoe manufacturer, Reebok International of Stoughton, Mass., recently introduced a running shoe which has two layers of air cushioning. Running shoe designers heretofore have sought to strike a compromise between providing enough cushioning to protect the wearer's heel but not so much that the wearer's foot will wobble and get out of sync with the working of the knee. The Reebok shoe uses air that moves to various parts of the sole at specific times. For example, when the outside of the runner's heel touches ground, it lands on a cushion of air. As the runner's weight bears down, that air is pushed to the inside of the heel, which keeps the foot from rolling inward too much while another air-filled layer is forcing air toward the forefoot. When the runner's weight is on the forefoot, the air travels back to the heel.
However, no past shoe designs, including the specific ones cited above, are believed to adequately address the aforementioned needs of the participant's foot and ankle system during walking and running activities in a manner that augments performance. The past approaches, being primarily concerned with cushioning the impact of the wearer's foot with the ground surface, fail to even recognize, let alone begin to address, the need to provide features in the shoe sole that will enhance the storage, retrieval and guidance of a wearer's muscle energy in a way that will complement and augment the wearer's performance during the walking, running and jumping activities.
Consequently, a pressing need still remains for improvements in sole construction for athletic footwear that will provide features that will enhance energy utilization.